// 定义 Circle 类
export class Circle {
  constructor(radius) {
    this.radius = radius;
  }

  get diameter() {
    return this.radius * 2;
  }

  get area() {
    return Math.PI * this.radius ** 2;
  }

  get circumference() {
    return 2 * Math.PI * this.radius;
  }
}